A vehicle exterior monitoring system is known in which a camera is installed outside a vehicle and the dead angles from the driver's seat are monitored from inside the vehicle cabin. For example, with the monitoring system disclosed in Non-Patent Document 1, it is possible to display a monitoring image of the exterior of the vehicle, by the driver pressing a switch, and the driver is able to drive while looking at the image to check safety.
The switching between display and non-display of the monitoring image can be performed automatically on the basis of the speed of the vehicle, as well as being performed by operating a switch. For example, the image can be displayed when travelling at low speed, and the display can be turned off automatically when the vehicle gathers more speed.
Furthermore, there is technology which automatically determines whether or not the vehicle is in a situation which requires a safety check of the periphery of the vehicle, and which displays a monitoring image in an active fashion. For example, in the invention disclosed in Patent Document 1, the width of the roadway on which the vehicle is travelling is determined by image analysis, and when the vehicle appears to be entering a broad road from a narrow road, it is determined that a safety check is necessary, and the monitoring image is displayed automatically. Consequently, the driver is able to check the safety at the periphery of the vehicle, without operating a switch.